1. Field of the Invention
The present invention relates to a plasma display and a driving method thereof, and more particularly, to a method for expressing gray scales of a plasma display.
2. Discussion of the Background
Generally, in a plasma display, a field (1 TV field) is divided into a plurality of respectively weighted subfields. Gray scales may be expressed by summing weights of subfields selected to display an image from among the subfields.
However, expressing gray scales using subfields may cause contour noise. For example, when using subfields with weights set to 2n, contour noise may occur when a discharge cell expresses the grayscales of 127 and 128 in consecutive fields. Therefore, the number of subfields may be increased to reduce the weight of a higher weighted subfield.
Also, the number of subfields may be increased to improve gray scale expression. For example, fourteen subfields may be used to express 512 gray scales. However, each subfield may have an address period for selecting a discharge cell to emit light in the corresponding subfield. In the address period, many switching operations are performed to select discharge cells to emit light, thereby generating power consumption. Additionally, an address discharge is generated to select discharge cells, thereby increasing power consumption. Accordingly, increasing the number of subfields may increase the number of address periods, as well as power consumption in the address periods.